zad 6
1. -3x = 2x - 10      
   -3x - 2x = 10
   -5x = 10 /-5
     x = -2

2. 2t - (3t - 1) = 6
   2t - 3t + 1 = 6
   -1t = 5 /-1
   t = -5

3. 2(x + 1) = x
   2x + 2 = x
   2 = x - 2x
   2 = -1x/-1
   x = -2

Zad 7
1. 3x + 6 = 21
   3x = 21 - 6
   3x = 15/3
   x = 5

2. 2(5x - 1) = 8
   10x - 2 = 8
   10x = 8 + 2
   10x = 10/10
   x = 1

3. -0,07(10x - 1) = 0,3x
   -0,7x - (-0,07) = 0,3x
   -0,7x + 0,07 = 0,3x
   -0,7x - 0,3x = -0,07
   -1x = -0,07/-1
   x = 0,07

4. 1/2(4y + 6) = 3
   2y + 3 = 3
   2y = 3 - 3
   2y = 0   ---- Chyba równanie sprzeczne lub nieoznaczone

5. 0,5x - 3 = -5
   0,5x = -5 + 3
   0,5x = -2/0,5
   x = -1

6. 2(x - 1) - 3(x + 1) = -8
   2x - 2 - 3x - 3 = -8
   2x - 3x = -8 + 2 + 3
   -1x = -3/-1
   x = 3